This invention relates to precision measuring apparatus, primarily coordinate measuring machines in which a probe assembly is mounted on a probe-supporting assembly which permits movement of the probe to positions where the probe stylus contacts a workpiece. The position of the probe when it contacts a workpiece is determined from position-sensing means provided in the apparatus.
In particular, the invention involves such measuring apparatus which is thermally stabilized to minimize errors attributable to thermal expansion or contraction.
The metrology industry has recognized the desirability of maintaining such apparatus at a constant temperature and, toward this end, coordinate measuring machines are often located in special rooms which are maintained at precisely controlled air temperatures. It is expensive to construct and operate such rooms, and their locations are not always convenient to the individuals who need to know the results of the measurements.
The present invention makes it possible to provide precise measuring apparatus at substantially any location in a factory, without also providing for precise control of room air temperature. The invention is less expensive and more convenient than a temperature controlled room, and is capable of providing comparable accuracy.